This report describes the characterization of the air source and the plume source at FLAME (the Fire Laboratory for Accreditation of Models by Experimentation). FLAME was designed to perform large indoor fire validation experiments and similar engineering sciences research activities. Validation experiments are a special class of experiment in that they are specifically designed for direct comparison with the computational models. Making meaningful comparison between the computational and experimental results requires careful characterization and control of the experimental features of parameters used as inputs into the computational model. Validation experiments must be designed to capture the essential physical phenomena, including all relevant initial and boundary conditions.